JPH04110278A - Molding of electromagnetic shield type resin outer plate - Google Patents

Abstract

PURPOSE:To surely provide the electromagnetic shielding performance free from the breakage of an electric conductive member by forming a shallow unevenness nearly on the whole surface of a metal mold, setting an Al foil and an SMC sheet in superposition, and joining the Al foil on the resin through the pressing molding at a prescribed temperature. CONSTITUTION:A flat Al foil 5 is set an a lower mold 1 having a wave-shaped unevenness 3, and an SMC sheet 4 is superposed, and upper mold 2 is lowered, and tightening is performed, and molding is carried out by applying the prescribed temperature and pressure. The resin of the SMC sheet 4 which is softend by the heating in molding flows in the direction of arrow, and pushes the Al foil 5 to the wave-shaped unevenness 3 of the lower mold 1, and deforms the Al foil to the wave shape 5A, and at the same time, the resin of the SMC sheet 4 is attached on the Al foil 5A. In this case, the SMC sheet 4 pressed by the upper mold 2 presses the Al foil 5 to the wave-shaped unevenness 3 of the lower mold 1 in the initial period of the molding, and even if the resin flows in the horizontal direction, the wave-shaped Al foil 5A does not move, and the Al foil 5A is prevented from being cut.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for molding a synthetic resin outer panel that has electromagnetic shielding properties.

[Conventional technology]

Traditionally, steel plates were used for the exterior panels of automobiles.
Recently, in response to the individualization of users, synthetic resin molded products, which are advantageous in terms of cost, have come to be used, and thermosetting resins reinforced with glass fibers are generally used. This glass fiber-reinforced thermosetting resin is made by impregnating unsaturated polynisder resin with glass fibers and forming it into a sheet.
Moltinck Combined J (SMC) material is mainly used, and thermoplastic polymers are also used for fenders, engine feet, etc.

If this resin part is used, for example, in the engine foot of a car, the resin engine foot cannot shield electromagnetic waves, which may cause electromagnetic interference such as malfunction of electronic equipment in the engine room or radio noise. do.

As a countermeasure to this problem, products have been developed in which aluminum foil is bonded to a resin engine foot. This product is shown in Figure 6 (A
), when molding the resin engine foot,
Place a flat aluminum foil 5 on the lower mold 1, and place the SMC on top of it.
The sheet 4 is placed thereon, the upper die 2 is closed, and a predetermined temperature and pressure are applied to form the resin molded product, and the aluminum foil 5 is brought into close contact with the resin molded product.

However, in this molded product, as shown in Figure 6 (B), the aluminum foil 5 and the resin layer 4a of the SMC sheet 4 come into plane contact, and are bonded together due to the bonding force between molecules on this contact surface. Therefore, the aluminum foil 5 may peel off during use due to insufficient adhesive strength. Furthermore, due to the lack of strength of the aluminum foil 5, the aluminum foil 5 may be torn due to flow of resin during molding.

As a measure to increase the adhesive strength, as shown in FIG. 7, a large number of holes 6a are made in the aluminum foil 6, and the resin 4a is made to overhang the back side of the holes during molding, and this anchor effect allows the aluminum foil 6 and the resin layer 4 to Improves adhesive strength with.

Also, JP-A-59-50870, JP-A-61-2
49877, as shown in FIG. 9(A), S
An aluminum foil 6 with a large number of holes 6a is sandwiched between the MC sheets 7.8 and set in the lower mold 1 for molding, as shown in FIG. 9(B). It has been proposed to use resin for the SMC sheets 7.8 on both sides, which are set on both sides, or to connect them at the holes 6a.

Furthermore, in Japanese Utility Model Application Publication No. 62-154913, a plurality of grains are arranged regularly on the surface of the mold, and the planar length of the grains is made smaller than the length of the metal fibers mixed in the resin. A conductive plastic mold has been proposed in which synthetic resin mixed with metal fibers is molded so that the metal fibers are not exposed on the surface of the molded product.

[Invention or problem to be solved]

Due to the anchor effect shown in Fig. 7, aluminum foil 6 and resin layer 4
However, since the aluminum foil 6 has a large number of holes 6a, the strength of the aluminum foil 6 is insufficient9. Therefore, as shown in FIG. When a force extending in the vertical and horizontal directions is applied to the holes a to d, the aluminum foil 6 or a to d.

It breaks between b-c, a-b, and d-c, causing poor conductivity in the molded product. The same applies to the molded product produced by the molding method shown in FIG.

Further, in the method described in the above-mentioned Japanese Utility Model Application Publication No. 62-154913, the metal fibers mixed in the resin do not necessarily come into contact with each other reliably, which may result in poor conductivity.

The present invention solves the above-mentioned problems by firmly bonding conductive members such as aluminum foil when molding a resin outer panel, and also prevents breakage of the conductive member to ensure electromagnetic shielding properties of the resin outer panel. The object of the present invention is to provide a method for molding a resin outer plate that is applied to a resin.

[Means and effects for solving the problem] The present invention forms shallow irregularities on almost the entire surface of a mold for molding the back surface of the outer panel, sets aluminum foil and SMC sheet in layers in the mold,
This is a method of forming an electromagnetic shielding resin outer plate in which the aluminum foil is bonded to a resin by pressure forming at a predetermined temperature.

At the beginning of the molding process, the softened SMC sheet resin or aluminum foil is pressed against the shallow irregularities of the mold and deformed to fit the mold, and after the aluminum foil is fixed so that it does not move, the resin flows and the mold is formed. Therefore, the aluminum foil does not break during molding, and since the bonding area between the aluminum foil and the resin of the molded outer panel increases, the two bond with sufficient adhesive force.

(Example) Embodiments of the present invention will be described with reference to the drawings.

Figure 1 shows a case in which the present invention is applied to molding an automobile engine foot. Figure 1 is a cross-sectional view of the mold showing the charged state, Figure 2 is an enlarged cross-sectional view during molding, and The figure is a perspective view of the molded product.

A flat aluminum foil 5 is set on a lower mold 1 having wavy irregularities 3 formed thereon, an SMC sheet 4 is stacked thereon, mold 1 2 is lowered and the mold is clamped, and a predetermined temperature and pressure are applied to form the foil. In this case, as shown in FIG. 1, the charging rate of the SMC sheet 4 is made as high as possible.

The resin of the SMC sheet 4 softened by heating during molding,
As shown by the arrow in Fig. 2, the aluminum foil 5 flows into the lower mold 1.
The aluminum foil is pressed onto the wavy unevenness 3 to deform the aluminum foil into the waveform 5A, and at the same time, the resin of the SMC sheet 4 is adhered to the aluminum foil 5A. At this time, the SMC sheet 4 pressurized by the upper die 2
In the initial stage of molding, the aluminum foil 5 is pressed against the wavy irregularities 3 of the lower mold 1 to blend in, and even after the resin flows horizontally, the wavy aluminum foil 5A does not move, so this aluminum foil 5A Never cut.

After molding, the molded product taken out from the mold has an increased bonding area between the corrugated aluminum foil 5A and the resin 4, as shown in FIG. 3, and is bonded with sufficient adhesive force.

The molded engine foot is electrically connected to the aluminum foil 5A on the back side at the hinge attachment part, and when this resin engine foot is attached to the vehicle body, it is electrically connected to the steel plate-equipped vehicle body side through the hinge.

Next, another embodiment will be described.

As shown in FIG. 4, a large number of circular shallow grains 13 are regularly formed on almost the entire surface of the lower mold l. Using this lower mold 1, a flat aluminum foil 5 and an SMC sheet 4 are stacked and molded in the same manner as in the previous embodiment.

In the early stage of molding, the softened resin flowing into the aluminum foil 5 or the lower blade is pressed against the grain 13 of the lower mold l, blends into the grain 13, deforms and fixes as shown in Figure 5B, and then the resin Since the aluminum foil 5B is molded by flowing in the horizontal direction, the aluminum foil 5B is not cut in this embodiment, and the bonding area between the aluminum foil 5B and the resin 4 of the molded product is increased to provide sufficient adhesive strength. Glue.

The shape of the grain is not limited to a circle, but can be any shape that forms shallow unevenness. Of course, it can be applied. .

(Effects of the Invention) According to the present invention, there is no fear that the conductive member for imparting electromagnetic shielding properties will break during molding of the resin outer panel, and after molding, the conductive member is firmly adhered to the resin layer, and the resin outer plate is firmly adhered to the resin layer. It has the effect of reliably imparting electromagnetic shielding properties to the board.

[Brief explanation of drawings]

Figure 1 is a sectional view of the mold showing the charged state, Figure 2 is an enlarged cross section during molding, Figure 3 is a perspective view of the molded product, and Figure 4 is the mold showing the charged state of another example. 5 is an enlarged sectional view during molding, FIGS. 6 to 9 show the prior art, FIG. 6(A) is a sectional view of the mold showing the charged state, and FIG. 6(B) is a perspective view of the molded product, FIG. 7 is a cross-sectional view of the molded product, and FIG. 8 is an explanatory diagram of the stress generated in the perforated aluminum foil.
9(A) and 9(B) 1:3: are sectional views of the mold showing the charged state, and 9th is a sectional view of the molded product. Lower mold 2, upper mold wavy unevenness 4: SMC sheet aluminum foil
13. Grain figure 3 figure 4 figure 5

Claims (1)

[Claims] Shallow irregularities are formed on almost the entire surface of a mold for molding the back side of the outer panel, aluminum foil and SMC sheet are stacked and set in the mold, and the aluminum foil is turned into resin by pressure molding at a predetermined temperature. A method for molding an electromagnetic shielding resin outer plate, characterized by joining.